


Shifting Moons

by The_Fictional_Truth



Category: Harry Potter - J. K. Rowling
Genre: Alternate Universe, Eventual Romance, F/M, M/M, Walburga black is not a good mother, Werewolf Sirius Black, eventual mention of abuse
Language: English
Status: In-Progress
Published: 2019-11-24
Updated: 2020-02-22
Packaged: 2021-02-26 04:33:32
Rating: Teen And Up Audiences
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 2
Words: 2,722
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/21547654
Author URL: https://archiveofourown.org/users/The_Fictional_Truth/pseuds/The_Fictional_Truth
Summary: Twelve-year-old Sirius Black knows something is going on with his best friend, Remus Lupin, and he thinks he can guess what.Remus Lupin is a werewolf.After an encounter in the library leaves him desperate to prove his theory and protect his friend, Sirius follows Remus into the Shrieking Shack on the night of a full moon. The Gryffindor gets more than he bargained for though when Remus bites him, leaving Sirius floundering.Now, Sirius has another question: are he and Remus the monsters everyone says they are?
Relationships: James Potter/Lily Evans Potter, Sirius Black/Remus Lupin
Comments: 4
Kudos: 16





	1. The Beginning

_The werewolf is found worldwide, though it is believed to have originated in northern Europe. Humans turn into werewolves only when bitten. There is no known cure. Once a month, at the full moon, the otherwise sane and rational wizard or Muggle afflicted transforms into a murderous beast. Almost uniquely among fantastic creatures, the werewolf actively seeks humans in preference to any other kind of prey._

"Well, that doesn't help much," Sirius muttered to himself, rubbing at his eyes as he slammed the copy of _Fantastic Beasts and Where to Find Them_ shut. "You, Mr. Newt Scamander, are no help at all."

Sirius Black had been in the library for hours, nose deep in books on werewolves, and had nothing to show of it. The only information on how to identify a werewolf had been on when they transformed, which didn't help him on his current mission.

As reckless as he seemed, and as much as his family would say the opposite, the twelve-year-old wasn't dumb. Sirius' knew something was up with Remus. The disappearing once a month, the growing number of scratches that littered the boy's body, the excuses he had given them about his mother being sick. None of it added up to him in a way that didn't scream 'huge secret.'

Of course, his being a werewolf was also a far stretch according to the books he'd read. Every single book had said that they were dangerous, cruel beasts that lost all control around the full moon, and it was hard for Sirius to picture Remus Lupin like that.

The young Gryffindor slowly reached out for another book, ignoring the pain behind his eyes. He wanted- no, needed to get enough information to confirm his suspicion before the end of the year. The raven boy didn't want to have to wait another three months before confronting his friend. He barely noticed the Slytherin approaching him from behind and jolted as the boy started to speak.

"I didn't know you could read, Black. I thought all the money your parents put into your education went to waste," Severus Snape sneered, and Sirius fought back the urge to hex him. He didn't need the other boy's misplaced jealousy complex interfering with his work.

"Not now, Snape. I'm trying to research my defense essay, and I need to focus," he spat out at the other boy, hoping the greasy git would get the hint to leave him alone.

"I was just making an observation," the Slytherin stated, irritation evident in his tone. The other boy leaned forward, and Sirius quickly moved to cover the title of the book. He smirked at the action. "Defensive much, Black? What, do you think I'm going to steal your idea for the essay? I doubt it would even be good enough."

"I just don't like having nosy grease balls looking over my shoulder," Sirius shook his head, moving to slide the small pile of books into his satchel. There was no way he'd be able to get back to work now that Snape had broken his focus. "Now, if you'll excuse me, I'll be heading back to my common room. I believe it's strictly snake-free."

"Wait!" The other boy called out, grabbing Sirius' arm. "Why are you researching werewolves? You turned in your essay a few days ago, and it's not on the curriculum until next year."

Sirius' brow furrowed. _How would he have known that?_ He'd specifically made sure no one had seen him turn it in. He ripped his arm away from Severus' grip, a scowl on his face. "Not that it's any of your business, but it's a personal interest."

Sirius moved to walk away again before frowning as he heard the Slytherin speak up. "It's because of Lupin, isn't it?"

The raven boy whipped around to face him. "And what exactly do you mean by that?"

"What, like you're the only one who's put together the clues?" Severus taunted, a malicious smirk on his face. "Anyone could have gotten to the same conclusion if they just looked closely. All of his disappearances happen around the full moon, and he always spends a few days in the infirmary afterward. You'd have to be an idiot to have not put the clues together by now."

"Well, you're wrong, Snape. Again, not that it's any of your business, but his mother is sick," Sirius stated matter of factly, holding his breath. Sure, he was trying to prove the same thing, but he wouldn't use the info against Remus. Severus Snape would. "He goes home once a month to see her and has to be checked out whenever he comes back. It's not some elaborate plot."

"You really expect anyone to actually believe that?"

"They should. It's the _truth_ ," Sirius insisted, pulling his bag close to his chest and pushing past the boy. "Now seriously, excuse me. I have a group of friends to get back to."

He made his way out of the library, forcing himself not to falter as the Slytherin called out to him again. "You know I'm right, Black. Why don't you just prove it and _follow_ him?"

Sirius kept walking, refusing to give the other boy any more time than he already had.

***

Remus was going to kill him.

This was a massive breach of the other boy's privacy, but Snape's words had gotten to him. Why _didn't_ he just follow the other boy and prove his theory? It wasn't like he was actually afraid of Remus.

So, Sirius had waited until Remus made his usual excuses to grab James' invisibility cloak, spitting out a random explanation to the others as he exited the common room. He crept behind the suspected werewolf, the cloak draped over his body. When they turned a corner, Sirus figured out where they were headed. They were walking the familiar path to the infirmary wing.

 _Was I wrong? Maybe he is just leaving to go see his mom,_ Sirius frowned, and his brows furrowed as he watched the other boy enter the infirmary.

Minutes passed, and the raven-haired boy began to get restless as Remus didn't reemerge into the hallway. Then, the door opened, and the tawny boy stepped out with Madame Pomfrey shortly behind him, a ratty blanket tucked into his arms. Sirius watched as they made their way out the doors and onto the campus grounds, before rushing to slip out of the closing door.

The fresh air of the incoming summer night washed over the preteen as he stepped out onto the stone path. He made sure to keep his footsteps light as he followed the pair down to the lake, keeping a fair distance.

Sirius felt his doubts further as the two made their way to the Whomping Willow, his brows furrowing. The Willow shuddered as the pairing approached, and the raven boy watched with confused amazement as Madame Pomfrey produced a large stick, poking at an unseen part of the roots. The tree stilled immediately, and the Gryffindor stared as a passageway in the tree made itself known.

As the pair made their way into the passage, Sirus broke away from where he'd frozen on the path. He quickly made his way towards the frozen tree. He paused as it came back to life, thinking through his options. The Gryffindor couldn't go in there with Pomfrey inside, nor did he know how he'd get inside either. Sirius would have to wait until she left to make his sneaky entrance into the passage.

Almost an hour passed before Pomfrey slowly made her reappearance from below, using the same stick to poke at what looked to be a knot in the trunk to still the tree.

 _That_ was his way in.

He watched the professor lay the stick on the ground by the lake before turning to make her way back up to the castle, the sky gradually growing darker the further she got. Sirius moved once she was out of his sight to scoop up the stick, carefully crossing the rest of the way to the tree.

The Gryffindor reached out his arm, just barely managing to still the tree before it hit him. He quickly ducked into the tunnel, not wanting to risk it reanimating and hurting him, and was greeted by a dirt slope.

The boy followed the long winding tunnel for a while, almost letting out a sigh of relief as he finally spotted light at the end of it. Then, the gut-wrenching screams reached Sirius' ears, followed by the sickening sound of bones breaking and readjusting.

The sound, according to his books, of someone transforming.

Sirius wanted nothing more than to run to comfort whoever was in pain but held himself back. He needed to wait until the shift was done, and then he could go comfort his best friend.

Screams quickly turned to low snarls, and the crunching of bones stopped before he was greeted with the sound of paws walking around. When the noises retreated further away, Sirius cracked open the door to the room.

The downstairs of a decrepit shack greeted the Gryffindor as he slid off the cloak. The wallpaper on the walls was torn, some of the wooden supports chewed. A chair was knocked over on the ground, and Sirius moved to turn it upright before moving further into the house. He made his way down the long hallway he'd heard the wolf walk down, pausing only to pick up the blanket on the floor.

He entered into another smaller room, blanket in hand, before spotting the makeshift bed. It was nothing but a cot and a few blankets, but the Gryffindor figured it worked for a one night a month basis. Sirius gently placed the sheet down onto the bed before spotting a toy.

He didn't hear the faint growl behind him as he reached for the toy, his hand barely touching it before the wolf's jaw clenched around his hand. 

Searing hot pain was all he felt as his body hit the ground.


	2. Chapter 2

The whistle of the train brought Sirius out of his memories, grounding him as his fingers traced softly over the scar on his hand.

Platform 9¾ bustled to life around him. Excited students chattered with parents about the upcoming year, and innocent first years looked around in nervous excitement. His eyes scanned the busy platform, looking for the familiar sight of unruly black hair and glasses. If Sirius could catch a glimpse of James, then he could make a quick escape from his family until winter break.

"Straighten up, Sirius. You're slouching," Walburga snapped, the hand resting on his shoulder's grip tightening slightly. Sirius nodded minutely at his mother, squaring his shoulders. "If I get word from Regulus that you're hanging with those insufferable friends of yours again-"

"You'll send me to live with Aunt Druella for the summer," the Gryffindor interrupted, "I know. You don't need to tell me-" The crack resonated in his ears as he felt the sting of his mother's hand connecting to his cheek. His own hand moved to hover above the tingling skin, shock running through his system.

Sirius was well acquainted with the sting of a slap, but that didn't dull the shock.

"Do  _ not _ interrupt me, child," Walburga hissed as she adjusted her robes, smoothing out the wrinkles of the fabric. "I am your mother, and you will show me some respect."

"Yes ma'am," Sirius forced out, averting his eyes from his mother.

He scanned the crowd again, spotting his James saying goodbye to his parents. He turned back to his own, frowning."I... I think I'm going to drop off my trunks now. I'll see you both when we come home for the holidays."

" _ Sirius Black _ !"

"Goodbye, mother! Goodbye, father!" the twelve-year-old called out, hurriedly pushing the cart towards the back of the train. He smiled at the man storing the trunks, murmuring out a small hello.

"Is that  _ the  _ Sirius Orion Black III, heir of the Black family fortune?"

The Gryffindor laughed, quickly turning around to wrap his arms around his best friend. The now-familiar smell of strawberries calmed him as they hugged, relief flooding through his system. He was  _ home _ .

"How was your summer, Sirius? Did your parents give you a hard time again?" James asked, pulling back from the hug as he quickly scanned Sirius for injuries. "I saw the she-devil hit you on the platform. What did you even do?"

"She was giving me the usual speech about hanging out with you guys, and I made the mistake of interrupting her." His hand reached up, ghosting a touch across his cheek. "Otherwise, it was fine. I stayed in my room for the days I wasn't required to socialize with my parents' friends, so they didn't have much reason to punish me. I missed you guys, though."

"It's a shame you weren't allowed to write to us. We missed you a lot too," the younger boy stated. Sirius felt his arm wrap around his shoulder, and he cracked a smile as they made their way into the train cars. "I tried planning a few pranks over the summer, but it didn't feel the same without you. I may be the face of the marauders, but you are definitely the mastermind."

"You flatter me, James," Sirius laughed. "How're Remus and Peter? Did you guys hang out over the summer like you planned?"

"I think they're okay! Their letters seem to indicate that way, at least," James stated, stopping them as they reached their usual compartment. "And we did! We hung out at the lake near my house and found out that Peter can't swim."

Sirius dropped into his usual spot on the benches, pulling his legs up with him. "How'd you guys not know that before you got there? Did he not mention it?" 

"He thought he would just hang out on the shore all day, but Remus pulled him into the water," the other boy laughed, taking his seat across from him. "Remus and I were laughing, but then he started flailing so we dragged him out. Then Rem offered to teach him to swim, but Pete wanted nothing to do with it. He got really angry." 

"Are we talking about Pete not knowing how to swim?" A pleasant voice asked, and Sirius whipped his head up. A grin formed on his lips as the smell of new books reached his nose, and his eyes landed on the werewolf standing in the doorway. Remus Lupin waved towards the raven boy, grinning. "Hey there, Siri." 

_ Sirius cried out in pain as his knees hit the ground. His hand was already starting to bleed as he cradled the limb to his chest, blinking back tears. _

_ He watched in fear as the wolf stalked towards him, his hackles raised as he growled. Sirius scrambled back away from the wolf and the cot. His back hit the torn wall, and he watched the wolf with rapt attention.  _

_ The wolf let out a low growl as he picked up the stuffed bear, dragging it away from the wizard and toward the ripped cot. Confusion flooded the boy’s system as the wolf curled up with it, bearing his teeth at Sirius. _

_ "What... what are you..?" Sirius breathed, pushing himself up from the floor with his good hand. "You... you don't want me to touch the bear?" _

_ The wolf- no,  _ Remus  _ huffed at him, letting out a grunt of confirmation. _

_ Sirius cracked a nervous smile as he moved against the wall, creeping over towards the door. "Alright, buddy... if I promise not to, will you let me out of here without following me?" _

_ Remus let out another low grunt, and Sirius nodded.  _ Okay. You can do this, Sirius. 

_ He watched the wolf as he began his slow exit from the room, keeping his uninjured hand held up in a sign of surrender. Sirius dropped it only to close the door as he crossed over the doorway, a sigh leaving his chest as he picked up the invisibility cloak, carefully draping it over his head. _

_ He needed to get his hand checked out, and he hoped that Madame Pomfrey wouldn’t ask too many questions.  _

"Hey there, Rem," Sirius grinned at the taller boy, patting the open seat next to him. "How was your summer?" 


End file.
